In recent years, integrated circuits of electronic devices become increasingly smaller, and the computing speed becomes increasing greater, and thus high temperature will be produced from the high performance of the electronic device such as a central processing unit (CPU), and the high temperature will retard the computing speed of the CPU or even cause a system down of a computer. To overcome this problem, a heat dissipating fan is generally installed to the CPU of the computer to enhance the heat dissipation capability. However, a motor is installed at the center of the heat dissipating fan, and the bottom area of the motor is superimposed onto the CPU chip, so that the air-blowing efficiency at the operating area of the center position will give rise of an leeward issue and the expected heat dissipation effect cannot be achieved, or the overheated CPU with a high temperature will cause a system down of the computer.
As disclosed in Taiwan Utility Model No. M287881, a heat dissipating fan comprises a plurality of diversion members, and at least one rib coupled between the diversion members, wherein the diversion member is extended in a curved direction and disposed in a non-concentric circular shape to define an opening, and a fan vane wheel with a plurality of vanes is installed, and the distance from an end of each vane to each diversion member is not consistent, so as to reduce the secondary flow phenomenon occurred between the vane and the diversion member. Although the heat dissipation effect can be improved by increasing the air input by the intervals, another problem of wind shear sound will be resulted easily by the wind resistance. In other words, the air pressure cannot be increased effectively, and noises will be produced. Obviously, the conventional heat dissipating fan requires feasible solutions and improvements.